<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<header>
    <% if(isLogin){ %>
    <span>欢迎回来~</span>
    <% }else { %>
    <button>登录</button>
    <button>注册</button>
    <% } %>
</header>

</body>
</html>